Well, Son Biten is (gaslit into believing herself to be) the reincarnation of Son Goku, so Yachie must be the reincarnation of master Roshi, she even has that (not dragon tortoise) turtle shell.

On another note, I was away from home for several days, during which I couldn't bring my computer and wacom along, that's why this illustration was done on Ibis Paint X, using my phone. This is the first time I tried to do a painting on smartphone, it was very difficult, the pen pressure was not ideal, and my phone was not the best fit for the job. But nevertheless, I really like the result.